Certain fuel injectors, such as those illustrated in commonly assigned U.S. Pat. Nos. 4,854,024; 4,967,959; 5,081,766; and 5,016,819, contain a seat member and a guide member that are joined together and assembled into the nozzle end of the fuel injector. A needle having a spherically shaped tip passes through a central circular hole in the guide member to dispose the needle's spherically shaped tip for coaction with a frustoconical shaped seat in the seat member. The needle is biased to seat its tip on the seat, closing the injector to flow. When the fuel injector is operated open, the needle is displaced away from the seat. The central circular hole in the guide member has a very close fit to the needle for guiding the reciprocal motion of the needle toward and away from the seat as the fuel injector is operated closed and open. If the guide member is not accurately aligned with the seat member, the guide member will not accurately guide the needle to and from the seat, possibly causing the injector to exhibit performance that is non-compliant with relevant specifications.
A prior practice for securing proper alignment of the guide member to the seat member comprised the use of a welding machine wherein accuracy of the alignment of the two parts was attained through close dimensional control of a locator pin on a fixture used to align the two parts preparatory to their being welded together and to support them while they were being welded together. Extremely close dimensional tolerances were imposed on the locator pin and related portions of the fixture. Mass production usage of the machine created wear on portions of the fixture, with consequent loss of accuracy in locating the two parts being welded together, so that replacement of parts of the fixture such as the locator pin inevitably became necessary. Significant time was required to make the necessary replacements for restoring the fixture to original condition, and substantial costs incurred on account of the time spent to fabricate the precision replacement parts and to precisely install them in the fixture.
The present invention comprises an improvement for aligning the locator pin to perpendicularity to a plane so that an installed locator pin that is not worn can be expeditiously re-aligned when needed, and so that a new or a replacement locator pin can also be expeditiously aligned when it is being installed. The invention is advantageous in that it is not especially complicated from the standpoint of the amount and nature of parts which it incorporates, and the actual alignment procedure can be accomplished with relatively simple adjustments.
The foregoing features, advantages, and benefits of the invention, along with additional ones, will be seen in the ensuing description and claims, which should be considered in conjunction with the accompanying drawings. The drawings illustrate a presently preferred embodiment of the invention according to the best mode contemplated at the present time for carrying out the invention.